Butylphthalide is the main component of the celery and the seeds thereof. It may be obtained not only by direct extraction from the natural plant celery seed oil, but also by synthesis. Chinese Patent No. 98125618.X discloses the use of levo-butylphthalide in the manufacture of a medicament against thrombosis and platelet aggregation, and clearly shows that levo-butylphthalide has the effect on regulating the function of NOS-NO-cGMP system and the metabolism of arachidonic acid in neural cells after cerebral ischemia. Chinese Patent No. 93117148.2 discloses the use of butylphthalide in the manufacture of a medicament for preventing and treating diseases caused by cerebral ischemia in a mammal or human, wherein the butylphthalide has no optically active. Butylphthalide, an oily liquid with strong flavour of celery, is represented by the following chemical formula:

The soft capsule, as a relatively novel dosage form, is particularly advantageous in the preparation of oily active ingredients into oral formulations, in which the active pharmaceutical ingredient is uniformly distributed in the diluent and fractional dose is accurate. Furthermore, the soft capsule has round and smooth shape, and is easy to be swallowed, which increases the compliance of patients.